TERRAPINS JOIN THE LIST OF TURTLES NEEDING PROTECTION
by Whit Gibbons
June 23, 2003
I once said diamondback terrapins were my favorite turtle. Imagine a
reptile with the dreamy eyes of a golden retriever and the unassuming
face of a manatee. Add the docile temperament of a lamb and the beauty
of the prettiest seashell. For extra credit include perseverance against
natural hazards of coastal weather, a sea full of predators, and a century
of human-caused adversity. This tough, attractive little turtle has
a record for getting through rough times with no complaints.
Restricted to the narrow brackish region between saltwater and fresh,
terrapins are the only U.S. turtle to live exclusively in coastal salt
marshes, from Cape Cod to coastal Texas. Sea turtles live in the ocean;
freshwater turtles live inland.
Among the prettiest turtles in the world, terrapins are highly variable
in color. Some are almost black, others milky gray, and some have splashes
of yellow or green. Their faces and shells look like hand-painted sculptures.
Their name comes from brightly colored, diamond-shaped concentric markings
visible on the upper shell of many. Females reach up to nine inches
in shell length and appear to be three times as large as the smaller
males, which are little larger than a person's hand.
Terrapins were seriously overexploited as a luxury food item in the
early part of the last century when terrapin stew was a delicacy in
many restaurants, and millions, especially the large females, were removed
from marshes and estuaries. But even today, things are not looking up
for my favorite turtle, as with many of the world's turtles. We know
that diamondback terrapins are in trouble in one location because we
have been studying them for more than twenty years and have clear records
of their declining numbers. A serious collapse has been observed in
the numbers of terrapins that inhabit the coastal waters around Kiawah
Island, South Carolina.
I just returned from two weeks of sampling terrapins in the coastal
salt marshes, a habitat most beachgoers only see from a car but one
that is home to these magnificent turtles. And they are clearly disappearing.
We were able to capture fewer than fifty turtles with an effort that
fifteen years ago would have yielded as many as two hundred. And virtually
all we caught were old, most being ones we had previously caught more
than a decade ago. Young turtles are not replacing those that die, which
could lead to local extinction.
The terrapin decline may have several causes, and no single culprit
has been identified. Crab trapping unquestionably kills terrapins each
year, especially small ones, when they enter and drown in crab pots
left underwater too long. Dead terrapins have been found in both commercial
and recreational crab traps in our study along the Kiawah River. Commercial
crab trappers are responsible for some terrapin deaths, but a more serious
cause may be from visiting tourists who abandon thousands of recreational
crab traps each year in all coastal states. These "ghost traps"
can do endless damage to terrapins and other marsh wildlife by continuing
to kill animals that enter them. People who leave untended traps mean
no harm, as they are unaware of the trouble they can cause. Thus a strong
educational program to inform visitors of the environmental hazards
of deserted traps might solve much of that problem.
absence of juvenile terrapins may also be exacerbated by the loss of
nesting habitat and siltation due to development, and the presence of
pesticides from agricultural runoff. Another suggested cause is an increase
in the mink population, an effective turtle predator, as the result
of a reintroduction program. Or perhaps a critical food source of young
turtles is no longer abundant.
the decline in terrapins may mean more than merely the loss of a spectacular
turtle. Terrapins may be harbingers of a deeper lying problem: that
the coastal marshes themselves are being environmentally stressed beyond
a sustainable limit, an issue that bears scrutiny. Whatever the cause,
terrapins are in far fewer numbers in the creeks we have studied, and
presumably the same holds for unstudied areas along much of the coast.
People who come to know terrapins may well decide these lovely animals
are among their own favorites, which should be justification enough
to be concerned about their welfare.
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